Facilitated Transport Nanocomposite Membranes for CO<sub>2</sub>/H<sub>2</sub> Separation: The Effect of Mobile Carriers
Wenqi Xu, Arne Lindbråthen, Xueru Wang, Zhongde Dai, Liyuan Deng
Abstract
High Resolution Image Download MS PowerPoint Slide Using CO 2 -selective membranes based on facilitated transport mechanisms has been reported as an energy-efficient approach for hydrogen purification from CO 2 -containing mixed gas streams. In this work, four CO 2 -philic mobile carriers, i.e., guanidine-based and amino acid-based salts, were introduced to a facilitated transport nanocomposite membrane to enhance the CO 2 /H 2 separation performance. The effects of the types and loading of mobile carriers on the CO 2 permeation properties were studied. Mechanisms that lead to enhanced CO 2 transport by mobile carriers in the facilitated transport membrane matrix and nanofiller–polymer interfaces are discussed. With an optimized loading of the selected mobile carriers, the AspK-based membrane doubled the CO 2 permeance without sacrificing the selectivity, while the ProK-based membrane increased the CO 2 /H 2 selectivity by 25% with a marginally increased CO 2 permeance. The optimized membranes show separation performances far above the upper bound of the CO 2 /H 2 upper bound.